This invention relates generally to an apparatus and corresponding method for pretrimming, trimming and performing a second operation on containers, such as plastic containers, and for trim scrap removal. The invention also relates to apparatii and corresponding methods for performing these functions separately in a modular fashion.
Containers, such as plastic bottles, are often formed by blow molding an injection molded preform. This process along with some additional operations are used to form xe2x80x9cwide mouth containersxe2x80x9d. These additional operations include, for example, pretrim and trimming operations, where a desired amount of material is cut from the container in one or more steps. Pretrim operations comprise performing a rough cut on the container to remove the bulk of the unwanted material prior to trimming. The trimming operation accurately trims the containers to a desired length. Once the desired amount of material is cut from the container, a curling operation may be performed. The curling operation smoothes and shapes the cut edge of the container.
One example of a trim station which performs trimming operations on containers is the CT500 trim station, where the CT500 is designed for trimming aluminum and steel containers. The CT500 trim station employs a trim head including an inner knife and an opposing knife with a D shaped blade. In the CT500 trim station, the container is supported by a workrest that is shaped like the inside of the container. The workrest is an integral part of the CT500 trim station. The CT500 trim station uses a knurling gear and a cutting insert that cuts a scrap trim section from the container, and then forms the scrap in a zigzag sheet shape. The CT500 trim station itself includes an integral vacuum assembly for holding the container to be trimmed. The scrap trim section is then ejected using forced air.
It would be desirable to provide an apparatus for processing containers, such as blown xe2x80x9cwide mouthxe2x80x9d containers into finished containers, where the processing components of the apparatus are provided in modular form. Thus, the apparatus may comprise one or more of the processing components as desired. It would further be desirable to provide an apparatus where the processing components may be operated independently. Thus, even if the apparatus comprises a number of processing components, the user may choose to operate only some of the components at a given time. Such a modular apparatus provides increased flexibility in processing blown containers which may be input into the apparatus in different stages of processing.
The trim station according to one aspect of the present invention does not require an integral vacuum assembly to hold the container. Instead the container may be held by a support which is outside the trim station itself. The trim station employs a C-knife in conjunction with an inner knife for performing the trim operation. The scrap trim section (or scrap ring) cut during the trim operation is held between the C-knife and inner knife until the C-knife is rotated to a home position. The scrap may be collected by a scrap tray and blown away by positive air pressure.
In accordance with one aspect of the present invention, there is provided an apparatus for trimming and performing a second operation on plastic containers, where the apparatus comprises a carousel having a main shaft, which conveys the containers about a central axis of the main shaft; a trim station positioned adjacent a first portion of the carousel, the trim station including a plurality of trimming heads which trim respective containers conveyed around the carousel thereby producing trimmed containers; and a second station positioned adjacent a second portion of the carousel, the second station including a plurality of second station heads which operate on the trimmed containers.
In accordance with another aspect of the present invention, there is provided an apparatus for trimming containers, where the apparatus comprises a plurality of trimming heads which trim respective containers, each of the trimming heads comprising a C-knife with a blade shaped as a C and an inner knife, wherein each of the respective C-knife and inner knife trim a respective container by simultaneously engaging the respective container; and a translation mechanism which simultaneously lowers each of the trimming heads to a respective container.
In accordance with another aspect of the present invention, there is provided an apparatus for pretrimming and conveying containers, wherein the apparatus comprises a starwheel having a starwheel central axis which engages and separates the containers and conveys the containers around the starwheel central axis; rollers which spin the containers conveyed around the starwheel central axis; a guide which guides the containers conveyed around the starwheel central axis; and a pretrim blade which pretrims the containers.
In accordance with another aspect of the present invention, there is provided an apparatus for operating on trimmed containers, wherein the apparatus comprises a plurality of heads which contact a portion of the trimmed containers as the containers are continuously rotated; and a translation mechanism which simultaneously lowers each of the heads to a respective container.
In accordance with another aspect of the present invention, there is provided an apparatus for removing scrap rings from trimmed containers, wherein the apparatus comprises a scrap removal tray; a translation mechanism which translates the scrap removal tray to a first regions and under the scrap rings so that the scrap removal tray may collect the scrap rings, and translates the scrap removal tray away from the first region so that the scrap removal tray removes the scrap rings from the first region; a scrap collector; and at least one air jet which blows the scrap rings in the scrap removal tray towards the scrap collector so that the scrap trim section collector collects the scrap rings from the scrap removal tray.
In accordance with another aspect of the present invention, there is provided a method of trimming and performing a second operation on a container, wherein the method comprises conveying the container along a path; trimming the container conveyed along the path as the plastic container is continuously spun about a central axis of the container to produce a trimmed container having a wide mouth; and operating on the trimmed container conveyed along the path including performing an operation on the mouth of the trimmed container as the trimmed container is continuously spun about the central axis.
In accordance with another aspect of the present invention, there is provided a method of trimming and performing a second operation on containers, wherein the method comprises conveying a plurality of containers along a path; trimming each of the plurality of containers conveyed along the path as each container is continuously spun about a central axis of the container to produce a plurality of trimmed containers having respective mouths; and operating on each of the plurality of trimmed containers conveyed along the path including performing an operation on the respective mouths of the trimmed containers.
In accordance with another aspect of the present invention, there is provided a method of trimming a container with a trim head having a C-knife with a C shaped blade with a gap in the blade and an inner knife, wherein the method comprises conveying the container to a position adjacent the trim head; providing a C-knife in a home position with the gap towards the inner knife; translating the trim head with the C-knife in the home position towards the container; rotating the C-knife in a first rotation so that the C-knife and the inner knife both engage the container and form a trimmed container, wherein the first rotation is not a full revolution; translating the trim head away from the trimmed container; and rotating the C-knife in a second rotation so that the C-knife is again in a home position with the gap towards the inner knife.
In accordance with another aspect of the present invention, there is provided a method of removing a scrap ring wherein the method comprises translating a scrap removal tray to a first region under a trim head in a first translation; collecting the scrap ring in the scrap removal tray at the first region; translating the scrap removal tray from the first region to a second region in a second translation; and blowing the scrap ring from the scrap removal tray to a scrap collector.
In accordance with another aspect of the present invention, there is provided a method of finishing the edge of a trimmed container with an edge finishing tool wherein the method comprises conveying the trimmed container to a position adjacent the edge finishing tool; translating an edge finishing tool within and contacting the trimmed container; continuously spinning the container while the container is contacting the edge finishing tool to form a finished container with a finished edge; and conveying the finished container away from the edge finishing tool.
In accordance with another aspect of the present invention, there is provided a method of pretrimming a container, wherein the method comprises conveying the container via a starwheel between the starwheel and a guide; and pretrimming the container while the container is conveyed between the starwheel and the guide, and while the container is continuously spun by rollers.
In accordance with another aspect of the present invention, there is provided a method of precise container positioning for a container trimming operation, wherein the method comprises translating a trim plate holding a plurality of trim heads for trimming the respective containers, each trim head having a respective neck control ring assembly mounted thereon; trapping a container between a control ring of a respective neck control ring assembly and a spindle support, the control ring contacting a top portion of the container and the spindle support contacting a bottom portion of the container.